pytorch/torch/nn/utils/fusion.py
Sam Tsai 2596113a79 Add fuse support for batchnorm with affine=False (#45474)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/45474

When batchnorm affine is set to false, weight and bias is set to None, which is not supported in this case. Added a fix to set weights to 1 and bias to 0 if they are not set.

Test Plan: Add unit test for testing fusing conv, batchnorm where batchnorm is in affine=False mode.

Reviewed By: z-a-f

Differential Revision: D23977080

fbshipit-source-id: 2782be626dc67553f3d27d8f8b1ddc7dea022c2a
2020-09-30 14:15:05 -07:00

29 lines
921 B
Python

import copy
import torch
def fuse_conv_bn_eval(conv, bn):
assert(not (conv.training or bn.training)), "Fusion only for eval!"
fused_conv = copy.deepcopy(conv)
fused_conv.weight, fused_conv.bias = \
fuse_conv_bn_weights(fused_conv.weight, fused_conv.bias,
bn.running_mean, bn.running_var, bn.eps, bn.weight, bn.bias)
return fused_conv
def fuse_conv_bn_weights(conv_w, conv_b, bn_rm, bn_rv, bn_eps, bn_w, bn_b):
if conv_b is None:
conv_b = bn_rm.new_zeros(bn_rm.shape)
if bn_w is None:
bn_w = torch.ones_like(bn_rm)
if bn_b is None:
bn_b = torch.zeros_like(bn_rm)
bn_var_rsqrt = torch.rsqrt(bn_rv + bn_eps)
conv_w = conv_w * (bn_w * bn_var_rsqrt).reshape([-1] + [1] * (len(conv_w.shape) - 1))
conv_b = (conv_b - bn_rm) * bn_var_rsqrt * bn_w + bn_b
return torch.nn.Parameter(conv_w), torch.nn.Parameter(conv_b)